[3] In his sophomore season, Watts averaged 25.6 points, 6.2 assists, and 2.8 steals per game and earned Detroit News second-team All-Area honors.

[1][4] As a junior, Watts averaged 26.8 points, 5.6 rebounds, 5.4 assists, and 3.1 steals per game, helping Old Redford Academy to a 19–6 record.

[1] For his senior season, Watts transferred with LaMelo Ball to SPIRE Institute and Academy, a boarding prep school in Geneva, Ohio.

On November 18, 2019, Watts recorded a then-career-high 11 points to go with another career-high 7 total rebounds as the Spartans routed Charleston Southern 94–46.

[16] He tied that mark of 21 points the next game, leading the team in scoring on February 25, 2020 as the Spartans won against (then) higher-ranked Iowa, 78–70.

[17] Watts played a crucial role in the Spartans' game against Penn State on March 3, as they came back from a 15-point deficit at half to win by 8.

He responded by leading the team in scoring with 20 points, including three crucial, late free throws to help stave off a Blue Devils comeback.

The next game, a 83–76 Spartan victory over Detroit Mercy, Watts once again received the start and led the team with a career-high 23 points.

In the next game against Oakland, Watts ran into foul trouble early and wound up with 9 points in 22 minutes as the Spartans won 109–91 to improve to 6–0 on the season.

In MSU's first conference win of the year, an 84–77 triumph over Nebraska, Watts scored 9 points coming off the bench, with two late free throws helping finish off the Cornhuskers.